To share or post a signup form:
On your dashboard, select Lists and click on Web Signup Forms,
The Signup Forms screen will appear. Under the Mailing List choose the necessary list. Learn more about web sign-up form customization in How to Setup and Customize a Web Signup Form
Use the link in an e-mail or forum, or post it in your social media profiles and feeds, to direct subscribers to your form. A link to the form appears at the top center of the screen (shown in the image above).
Click the button just to the right to copy the link to the clipboard and paste the link wherever you need it to direct subscribers to the signup form.
Post your web signup form using HTML code:
Use the HTML code to embed the form on your website, blog, or company's Facebook page. Learn more in Embed a Signup Form On a Website.